Funny thing about resonance. When you hear it, feel it, or see it something is about to be destroyed. Usually self-destruct is sooner rather than later. It is not unusual for resonance frequencies to drive up the stress loads by two orders of magnitude.

You might want to consider doing something about the resonance noise. Even if the prop is strong enough to withstand the stress tremendous vibration loads are being transmitted to the firewall and to the rest of the airframe. The weaker glue joints will begin to fail first and won’t be noticed. The end result is most likely catastrophic failure at an inopportune time.

It usually ruins the day.

Bill S